A Calculation Model for Cooling Rate of Aluminum Alloy Melts during Continuous Rheo-Extrusion

The melt temperature of aluminum alloys plays a significant role in determining the microstructure characteristic during continuous rheo-extrusion. However, it is difficult to measure the actual melt temperature in the roll-shoe gap. In this work, based on the basic theory of heat transfer, a calculation model for heat transfer coefficient of cooling water/roll interface and melt/roll interface is established. In addition, the relationship between the temperature at the melt/roll interface and the velocity of cooling water is investigated. Combined with the CALPHAD calculation, the melt temperature during solidification in the continuous rheo-extrusion process is calculated. Using this model, the cooling rate of an Al-6Mg (wt.%) alloy melt prepared by continuous rheo-extrusion is estimated to be 10.3 K/s. This model used to determine the melt parameters during solidification provides a reference for optimizing the production process of continuous rheo-extrusion technology.